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. 2020 Sep 28;99(12):6542–6548. doi: 10.1016/j.psj.2020.09.037

Figure 4.

Figure 4

The pathogenicity and immunosuppression to layer chickens induced by the IBDV novel variant strain SHG19. (A) The BW of 42-day-old SPF layer chickens. (B) The BBIX values of the infected and control groups of vaccinated SPF layer chickens at 21 d p.i.. (C) The spleen/BW ratio at 21 d p.i.. (D) Antibodies titer to the ND vaccine of layer chickens determined by homologous HI assay. The mean value and SD (error bars) from 10 independent samples are shown (∗P < 0.05, ∗∗P < 0.01; NS, not significant). Abbreviations: BBIX, bursa:BW index; d p.i, days post-infection; HI, hemagglutination inhibition; IBDV, infectious bursal disease virus; ND, Newcastle disease; SPF, specific pathogen free.